1. Field of the Invention
The present invention relates to a magnetron. More particularly, the present invention relates to a magnetron that can generate a high frequency energy of the Tera Hertz (THz) band.
2. Description of the Related Art
The magnetron generates a high-frequency energy and is widely used in home appliances such as a microwave oven, as well as in industrial applications, such as the areas of data signal transmitting, medicine, and biotechnology.
Briefly looking into the structure and principle of magnetrons, a magnetron generally comprises a cylindrical positive pole, a negative pole on a central axis of the cylindrical positive pole, a magnet which forms a magnetic field in parallel with the axis direction of the negative pole, and a resonance cavity for generating a resonance of electric current. When a high voltage is supplied to the negative and positive poles of the magnetron with the above structure, electrons are emitted from the negative pole. The electrons collide with the resonance cavity, moving in a cycloid, due to interaction between an electric field and the magnetic field of the negative and positive pole, such that an electric current flows. Due to the continuous collision of electrons, the electric current is oscillated in the resonance cavity. The resonance cavity is electrically equivalent to a series circuit of an inductor and a capacitor, and if the frequency of the electric current is accorded with a resonance frequency of the series circuit, a high-frequency energy is generated that is an electromagnetic wave of the resonance frequency of high frequency. The high-frequency energy is picked up by a coupling iris and emitted by an antenna to a necessary place.
The energy produced in accordance with the above principles has a frequency of approximately 95 GHz and below. However, a study has recently increased the frequency of the energy generated from a magnetron to an energy band that is potentially in the Terahertz region (e.g., 300 G Hz˜3 THz).
To increase the frequency of the energy, a large amount of electric current may flow to the negative pole. However, the negative pole may be easily deteriorated as the temperature thereof rises. Further, the negative pole may be damaged as emitted electrons return towards the negative pole and collide with the negative pole. Therefore, such conventional methods shorten the lifespan of the negative pole. Recently, a study has obtained a higher frequency by reducing the resonance cavity.